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Description of Study Test Case

The following figures show schematically the general set-up of the wind tunnel experiment and the cases investigated. In general, the urban model (either with even height, marked A1, or with uneven height, marked A2) was positioned in the middle of the wind tunnel test section (Fig. 1a). To simulate the oblique wind direction, the model was rotated 45 degrees in its centre (corresponding to the centre of the coordinates $x,z,y$ ). The studied street canyons were positioned in the middle of the urban model (green rectangles in Fig. 2a and b), as well as the line source near the ground (the red line in Fig. 2a and b). For model A1, only the right street canyon (designated A1-R, viewed from downstream) was investigated due to symmetry, while the right (A2-R) and left (A2-L) street canyons were investigated in model A2 due to the uneven roof height. Upstream of the model, a neutrally stratified atmospheric boundary layer was simulated using roughness elements and Irwin spires in the development section of the wind tunnel. Based on the mean height of the building ( $H$ ) and the free flow velocity $U_{ref}=6.2$ $ms^{-1}$ (which was used as the reference velocity), the flow was completely independent of the Reynolds number (i.e. Failed to parse (syntax error): {\displaystyle Re_{B} = HU_{ref}/&nu = 24400} , where Failed to parse (syntax error): {\displaystyle &nu} is the kinematic viscosity of the air).

Figure 1: Schematic representation of the experimental setup in the wind tunnel with reference to the wind tunnel coordinates (x,y,z). All dimensions are given in mm. Adapted from [1]

Contributed by: Štěpán Nosek — Institute of Thermomechanics of the CAS, v. v. i.

Front Page

Introduction

Review of experimental studies

Description

Experimental Set Up

Measurement Quantities and Techniques

Data Quality and Accuracy

Measurement Data and Results